I like sardines straight from the can, slapped on a piece of bread so all the fishy oils sink into the bread and the the flesh smears and flattens just so. I like that the bones on very small sardines are soft enough to be eaten along with the fish. A couple of fillets make for an instant meal if the bread is good and the fish is firm and un-mealy.
Purely anecdotal research tells me that people still harbor a prejudice against canned sardines, or even canned oily seafood as a whole. Like mackerel, sardine flesh is dense, rich and oily.
But fresh sardines are another matter. Their taste is unmistakably sardine-esque, yet toned down for a wider audience. Cooked properly so that the flesh has only begun to flake, the flesh is tender and not very fishy at all. If you can get sardines that are very fresh, the easiest thing to do is to grill or broil them so the skin chars a little. Sprinkle with salt, freshly ground pepper, and lemon or vinegar.
If, however, you find that fresh sardines are still too fishy for your taste, consider a simple marinade. I use ginger to combat the fishiness, a little wine for depth, soy sauce, and a dash of salt and sugar. Other things you could throw into the marinade: a splash of vinegar, lemon, lemongrass, chili peppers, shallots, and garlic. The marinade not only brines and preserves the fish, it acts as a palliative for the worst of the fishiness. I would even serve this to a sworn sardine hater.
You'll find fresh sardines at Japanese, Korean, and Chinese markets. (Also, check at other fishmongers who understand that some humans enjoy eating smelt and baitfish.) The sardines will be no more than four or five inches in length, but that gives you plenty of meat and the skeleton comes right off once you've eaten a side.
Sardines are often sold without being eviscerated, though the fish are so small that it's just a matter of reaching in and gently pulling out the slip of viscera inside. Once marinated, they may be broiled, grilled, or pan-fried in minutes.